gnu1987/gnucmds/mv.c

/* Copyright (C) 1986 Free Software Foundation, Inc.

		       NO WARRANTY

  BECAUSE THIS PROGRAM IS LICENSED FREE OF CHARGE, WE PROVIDE ABSOLUTELY
NO WARRANTY, TO THE EXTENT PERMITTED BY APPLICABLE STATE LAW.  EXCEPT
WHEN OTHERWISE STATED IN WRITING, FREE SOFTWARE FOUNDATION, INC,
RICHARD M. STALLMAN AND/OR OTHER PARTIES PROVIDE THIS PROGRAM "AS IS"
WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY
AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE PROGRAM PROVE
DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR
CORRECTION.

 IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW WILL RICHARD M.
STALLMAN, THE FREE SOFTWARE FOUNDATION, INC., AND/OR ANY OTHER PARTY
WHO MAY MODIFY AND REDISTRIBUTE THIS PROGRAM AS PERMITTED BELOW, BE
LIABLE TO YOU FOR DAMAGES, INCLUDING ANY LOST PROFITS, LOST MONIES, OR
OTHER SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
USE OR INABILITY TO USE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR
DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY THIRD PARTIES OR
A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS) THIS
PROGRAM, EVEN IF YOU HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY.

		GENERAL PUBLIC LICENSE TO COPY

  1. You may copy and distribute verbatim copies of this source file
as you receive it, in any medium, provided that you conspicuously
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"Copyright (C) 1986 Free Software Foundation, Inc"; and include following the
copyright notice a verbatim copy of the above disclaimer of warranty
and of this License.

  2. You may modify your copy or copies of this source file or
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    b) cause the whole of any work that you distribute or publish,
    that in whole or in part contains or is a derivative of this
    program or any part thereof, to be freely distributed
    and licensed to all third parties on terms identical to those
    contained in this License Agreement (except that you may choose
    to grant more extensive warranty protection to third parties,
    at your option).

  3. You may copy and distribute this program or any portion of it in
compiled, executable or object code form under the terms of Paragraphs
1 and 2 above provided that you do the following:

    a) cause each such copy to be accompanied by the
    corresponding machine-readable source code, which must
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    b) cause each such copy to be accompanied by a
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    copy of the corresponding source code, to be distributed
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    c) in the case of a recipient of this program in compiled, executable
    or object code form (without the corresponding source code) you
    shall cause copies you distribute to be accompanied by a copy
    of the written offer of source code which you received along
    with the copy you received.

  4. You may not copy, sublicense, distribute or transfer this program
except as expressly provided under this License Agreement.  Any attempt
otherwise to copy, sublicense, distribute or transfer this program is void and
your rights to use the program under this License agreement shall be
automatically terminated.  However, parties who have received computer
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*/

/*
 * Mv.  Usage is either `mv f1 f2' or `mv f1 f2 ... dir'.  In either case,
 *  two options, -i and -f, which must be placed before all files, may be
 *  specified.  The null option, -, indicates that no options, only files,
 *  follow and may be used to specify file names beginning with a - sign.
 *  The -i option causes mv to require confirmation from the user before
 *  performing any move which would destroy an existing file.  The -f option,
 *  overriding the -i option, causes mv to assume a 'y' answer to all
 *  questions it would normally ask (and not ask the questions).  There are
 *  two questions:
 *
 *	Move f1 (removing f2)?
 *	Override mode 0nnn for fn?
 *
 * The first one is caused by the -i option, the second by a move which would
 *  destroy an existing file when the existing file's mode prohibits writing.
 *  This test is slightly different from the test 4.2bsd mv makes; 4.2 mv
 *  merely checks whether the user can write the file.  This actually checks
 *  the write bits in the mode.  The difference shows when super-user tries
 *  to mv onto a file with no write bits set.
 *
 * Author Mike Parker
 */

/*
 * This program assumes the following:
 *
 *	errno, stat(), access(), rename() semantics as in 4.2
 */

#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>

char *pgm;

int interactive; /* the -i option */
int force; /* the -f option */

int nargs; /* number of arguments to process */
char **args; /* the remaining arguments */

/* strip off (and interpret) any leading options from the arguments */
get_options()
{
  interactive = 0;
  force = 0;
  while (1)
    {
      if (**args != '-')
	return;
      if (*++*args == '\0')
	{
	  args ++;
	  nargs --;
	  return;
	}
      for (; **args; ++*args)
	switch (**args)
	  {
	  case 'f':
	    force = 1;
	    break;

	  case 'i':
	    interactive = 1;
	    break;

	  default:
	    fprintf (stderr, "%s: bad flag -%c\n", pgm, **args);
	    break;
	  }
      args ++;
      nargs --;
    }
}

/* check whether the file is a directory */
int
isdir (fn)
     char *fn;
{
 struct stat stb;

 return (stat (fn, &stb) >= 0 &&
	 (stb.st_mode & S_IFMT) == S_IFDIR);
}

main (ac, av)
     int ac;
     char **av;
{
  pgm = *av++;
  ac --;
  if (*av == 0)
    {
      usage ();
      exit (0);
    }
  args = av;
  nargs = ac;
  get_options ();
  if (nargs < 2) /* too few arguments */
    {
      usage ();
      exit (1);
    }
  if ((nargs > 2) && !isdir (args[nargs-1])) /* >2 args and last not dir */
    {
      fprintf (stderr,
	       "%s: when moving multiple files, last argument must be a directory",
	       pgm);
      exit (1);
    }
  for (; nargs > 1; args++, nargs--) /* move each arg but last onto the last */
    movefile (args[0], args[nargs-1]);
}

/* Move `from' onto `to'.  Handles case when to is a directory. */
movefile (from, to)
     char *from;
     char *to;
{
  if (isdir (to)) /* target is a directory, build full target filename */
    {
      char *cp;
      char *newto;
      char *rindex();
      int l;

      cp = rindex (from, '/');
      if (cp)
	cp++;
      else
	cp = from;

      l = strlen (to) + 1 + strlen (cp) + 1;
      newto = (char *) alloca (l);
      sprintf (newto, "%s/%s", to, cp);
      to = newto;
    }
  do_move (from, to); /* perform the move */
}

/* Used for confirmation of the move in various cases.  Reads one line and
    returns true iff that line begins with y or Y. */
int
yes()
{
  char c;
  int rv;

  c = getchar ();
  rv = (c == 'y') || (c == 'Y');
  while (c != '\n')
    c = getchar();

  return rv;
}

/* Perform a move.  Handles cross-filesystem moves. */
do_move (from, to)
     char *from;
     char *to;
{
  extern int errno;

  if (access (to, F_OK) >= 0) /* target exists */
    {
      struct stat stb;
      if (interactive && !force)
	{
	  printf ("Move %s (removing %s)? ", from, to);
	  if (! yes ())
	    return;
	}
      if (stat (to, &stb) < 0) /* we can't stat it?!? */
	{
	  fprintf (stderr, "%s: strange error in stat() on %s (%s not moved): ",
		   pgm, to, from);
	  perror (0);
	  return;
	}
      /* check for write access to target */
      if ((access (to, W_OK) < 0 ||
	   (stb.st_mode & ((S_IWRITE>>6)*0111)) == 0)
	  && !force )
	{
	  printf ("Override mode %04o for %s? ", stb.st_mode & 0777f ,to);
	  if (! yes ())
	    return;
	}
    }
  if (rename (from, to) < 0)
    {
      if (errno == EXDEV) /* rename() failed on cross-filesystem link */
	{
	  int ifd;
	  int ofd;
	  struct stat stb;
	  char buf[1024];
	  int len;

	  /* do the following to perform the move:
	     unlink the target
	     open both files
	     copy the permission bits from the source to the target
	     copy the source to the target
	     close both files
	     if no error so far, unlink the source
	     */
	  if (unlink (to) < 0)
	    {
	      fprintf (stderr, "%s: cannot remove %s: ", pgm, to);
	      perror (0);
	      return;
	    }
	  ifd = open (from, O_RDONLY, 0);
	  if (ifd < 0 )
	    {
	      fprintf (stderr, "%s: cannot read %s: ", pgm, from);
	      perror (0);
	      return;
	    }

	  ofd = open (to, O_WRONLY|O_CREAT|O_TRUNC, 0777);
	  if (ofd < 0 )
	    {
	      close (ifd);
	      fprintf (stderr, "%s: cannot create %s: ", pgm, to);
	      perror (0);
	      return;
	    }
	  fstat (ifd, &stb); /* can't fail if given good args */
	  fchmod (ofd, stb.st_mode & 0777); /* again, can't fail */
	  while ((len = read (ifd, buf, sizeof (buf))) > 0)
	    {
	      int wrote = 0;
	      char *bp = buf;

	      do
		{
		  wrote = write (ofd, bp += wrote, len);
		  if (wrote < 0)
		    {
		      fprintf (stderr,
			       "%s: error writing %s while copying from %s, move not completed: ",
			       pgm, to, from);
		      perror (0);
		      close (ifd);
		      close (ofd);
		      return;
		    }
		} while ((len -= wrote) > 0);
	    }
	  if (len < 0)
	    {
	      fprintf (stderr,
		       "%s: error reading %s while copying to %s, original not removed: ",
		       pgm, from, to);
	      perror (0);
	      close (ifd);
	      close (ofd);
	      return;
	    }
	  close (ifd);
	  close (ofd);
	  if (unlink (from) < 0)
	    {
	      fprintf (stderr,
		       "%s: cannot remove %s after successful copy to %s: ",
		      pgm, from, to);
	      perror (0);
	      return;
	    }
	}
      else
	{
	  fprintf(stderr,"%s: %s not moved to %s: ",pgm,from,to);
	  perror(0);
	}
    }
}

/* called to print out the usage message */
usage()
{
  fprintf (stderr,
	   "Usage:  %s [-if] [-] f1 f2  or  %s [-if] [-] f1 ... fn dir\n",
	   pgm, pgm);
}